Trial manufacture of an ultra-high sensitive video-microscope system with and image-processor and its applications to cell biology

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A video-microscope system was developed, in order to visualize microscopic objects under an extremely-low intensity light. Using this system, intracellular release of calcium ions at fertilization and artifical activation was recorded in eggs of sea urchin, starfish, medaka, frog and golden hamster, which had been injected with aequorin, a photoprotein sensitive to free calcium ions. In these eggs, the increase in intracellular calcium ion concentration was started at the site of sperm entry or the site of artificial activation and it propagated over the cell cortex toward the antipod. This calcium wave preceded the wave of the breakdown of cortical alveoli or cortical granules, suggesting that the increase in calcium ions induces the cortical change.Periodic changes in intracellular calcium ions accompanying cell cycle were recorded in fertilized medaka and sea urchin eggs injected with aequorin. In both eggs, intracellular calcium ion concentration attained a minimum during cleavage.Transient and localized increases in intracellular calcium ions accoumpanying amoevoid movement and protoplasmic streaming in slime mold were recorded using aequorin as a probe.Changes in intracellular calcium concentration were also recorded using fura 2, a fluorescent probe for calcium ions.